#399 - Canaries In The Ocean, 20-Jul-1994

Does pollution really matter? Just look at the oceans. In Puget Sound
in the far northwest, the Pacific salmon and steelhead are gone; this
year for the first time there will be no Pacific salmon fishing at all.

Near Gloucester and New Bedford, Massachusetts, the oldest U.S. fishing
grounds, the three main commercial fish --cod, haddock, and flounder --
have all but disappeared. The fishing grounds are barren and the
Atlantic fishermen have asked the federal government to treat them like
earthquake disaster victims.[1]

In the Chesapeake Bay, where oysters were once abundant beyond
imagining, they are now scarce and stunted by disease. Researchers at
University of Maryland say the oysters' immune systems have been
weakened by pollution; now disease and overfishing are wiping them out.
[2] In the Gulf of Mexico, grouper and red snapper have always been
bounteous, but no more.

Worldwide, 13 of 17 principal fishing zones are depleted or in steep
decline. The causes? Pollution and overfishing, United Nations and U.S.
government experts agree.[1]

If the fish are being harmed by contamination what about other marine
species --the sea turtles, the walruses, the sea lions, and the seals?

Between 1986 and 1991, green sea turtles began appearing with massive
tumors called fibropapillomas. Up to half of all turtles of this
species now have these huge growths which can kill them by impeding
their ability to swim and eat. The fibropapillomas have been linked to
infection by a herpes-like virus.[3]

In 1987, seals in Siberia's Lake Baikal died in large numbers from a
distemper virus --one later recognized as quite similar to the
distemper microbe that kills dogs, foxes and wolves by damaging their
respiratory, gastrointestinal, and nervous systems.

In 1988, white-sided dolphins experienced a mysterious, lethal epidemic
in the waters off Lubec, Maine. That same year in the North and Baltic
Seas, some 25,000 harbor seals --about 60 to 70% of all the seals
living there --abruptly died. Subsequent investigation identified the
source of the epidemic as the canine-like distemper virus.

In 1989, 274 bottlenosed dolphins were found dead along the shores of
the Gulf of Mexico, many of them covered with a strange fungus. Between
1990 and 1992 more than 1000 Mediterranean striped dolphins died of an
infection resembling canine distemper. Tests on the bodies of seals
from the Gulf and from the Mediterranean revealed high levels of PCBs
[polychlorinated biphenyls] in their tissues. PCBs are industrial
chemicals spread throughout the planet by a single chemical company,
and its licensees, between 1929 and 1976.

All these episodes involved populations of animals that carried high
levels of organochlorine compounds in their tissues. Now scientists in
the Netherlands have evidence that industrial pollution damages the
immune systems of marine mammals.[4]

In a controlled experiment, Dutch virologist Albert D.M.E. Osterhaus of
Erasmus University in Rotterdam fed two groups of harbor seals fish
from different sources. One group of seals received relatively clean
fish from the North Atlantic and the other group received fish from the
industrially-polluted Baltic sea. The Baltic fish contained 10 times as
much organochlorine pollution as the Atlantic fish. Osterhaus
emphasizes that both kinds of fish were taken from catches destined for
human consumption.

For 2 years, the researchers sampled blood from the seals every six to
nine weeks and made various measurements of immune system function.
Almost immediately after the experiment began, vitamin A levels dropped
20 to 40 percent in the blood of seals fed fish from the Baltic and
remained low throughout the 2-year experiment. Vitamin A is associated
with disease resistance; lower vitamin A levels in the blood correspond
to greater vulnerability to disease.

The Baltic-fed seals showed other changes in their blood. The
concentration of granulocytes was consistently elevated 10 to 15
percent, compared to the Atlantic-fed seals. Granulocytes are white
blood cells that fight bacterial infections. Osterhaus speculates that
the Baltic-fed seals may have suffered from higher levels of chronic
infection.

Seals fed Baltic fish showed another important change: the level of NK
cells in the blood remained 20 to 50 percent below normal throughout
the study. NK cells are "natural killer" cells that attack foreign
bodies in the blood, thus providing important immune protection.

Other key components of the immune system were compromised in the
Baltic-fed seals. In a healthy immune system, B cells produce
antibodies and T cells orchestrate the immune response to foreign
invaders. In the Baltic-fed seals, the T-cell response to a standard
set of antigens dropped 25 to 60 percent, compared to the Atlantic-fed
seals. After interviewing Osterhaus, Janet Raloff reported in SCIENCE
NEWS that, "Additional, unpublished data suggest that the antibody
responses of B cells also were impaired."

The Osterhaus experiments are not the final word on what's been killing
seals for the last 10 years, but they are highly suggestive that
pollution harms the immune system of marine mammals. Because they have
large stores of blubber, because organochlorine compounds accumulate in
fat, and because they eat high on the food chain, marine mammals tend
to collect organochlorine compounds in their bodies. During periods of
stress (such as illness or famine) these organochlorine compounds can
move back into the blood stream and be distributed throughout the body.

Last December a group of wildlife specialists, representing diverse
disciplines, met to discuss the global situation. In April they issued
a joint statement that said, in part,[5]

"We are certain of the following:

"Declines in a number of species and many taxa (including plants) are
in progress on the North American continent. Some of these declines are
related to exposure to man-made chemicals. Such declines are not solely
a U.S. or North American problem but are occurring on a global
scale....

"Populations of many long-lived species are declining, some to the
verge of extinction, without society's knowledge....

"Wildlife are exposed to compounds [industrial chemicals] that disrupt
development of the reproductive, immune, nervous and endocrine systems
and thereby can lead to population instability. The pollutants of
greatest concern affect cellular and molecular processes that regulate
developmental, endocrine, and immunological functions....

"Chemical releases on one continent may not only affect animals on that
continent but animals on other continents and in other hemispheres.
They are carried as particulates or gases in the air, surface waters,
groundwater, and ocean currents across or between continents and by
animals that travel long distances from the site of contamination. The
contaminant, therefore, can enter the food web in places remote from
the site of release....

"Contamination of apparently useful habitat is not always visible and
may not cause overt lethality. Instead, contaminants may cause
population-threatening changes in functionality. For example,
populations may not be able to recover from infectious diseases because
of: immunosuppression; the inability to obtain sufficient food or avoid
predators; the loss of parenting instinct because of neurotoxicological
effects; or the result of abnormal sexual development of anatomy or
behavior because of endocrine disruption....

"We estimate with confidence that:

"In many cases wildlife and humans have exceeded their capacity to
compensate for exposure to chemicals....

"When an animal is exposed at the same time to many chemicals that
individually are at non-toxic levels, additivity, antagonism,
potentiation, and synergy [multiplier effects] can result in
unpredictable consequences. Concomitant [simultaneous] exposure to
multiple chemicals can cause massive or subtle, but potentially tragic,
effects....

"Wildlife are reliable sentinels of effects of chemicals on human
populations....

"We believe that:

"Traditional assessments of risks posed by single chemicals are not
adequate for assessing the risks for embryos exposed to multiple
chemicals....

"Until more people understand the insidious nature of developmental
toxicants, little will change. More popular press articles and other
media should broadcast the message about the effects of developmental
toxicants using the wildlife/human connection...."

Miners used to keep canaries in cages in the coal mines, to warn of a
buildup of toxic gases. When the canaries died, it served as a stark
warning that conditions were deteriorating dangerously.

Today our canaries are in the ocean. Only fools will ignore them.

--Peter Montague

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[1] Timothy Egan, "U.S. Fishing Fleet Trawling Coastal Water Without
Fish," NEW YORK TIMES March 7, 1994, pgs. A1, B7.